The Legacy of Sidonia
by NeoSolstice
Summary: It's been ten years since seed ship Sidonia has left the Lem system for new worlds. Though the length of contact was long, Sidonia had always kept in touch with Lem-VII since it's departure. One day, contact with Sidonia mysteriously vanishes. A few months later, Mizuki, one of Sidonia's escort ships had returned to the Lem system, nearly destroyed. What on Earth has happened?
1. Prologue

**Disclaimer: I do not own Knights of Sidonia. Credits to Nihei-sensei for the excellent story! The story I'm writing here would take place after the events that occurred on Lem. I hope you'll enjoy the read!**

* * *

 **Prologue**

It's not like she never seen Gauna before.

Coming out of the Gauna's mouth, dozens of tongue-like tendrils reveal themselves as the 'lead head' cautiously inch towards the Yukimori. Despite looking like an abomination lacking intelligence of any kind, this hideous creature seems awfully wary of of her actions. Stretching its head and an arc above the Garde, the creature seems to be analysing Nodoka's machine, despite it not moving at the moment. With a small hunch, floating in her head, Nodoka activated some of her artificial Kabi-blades. With the blades roaring into action, the Gauna quickly shrieked back, but not before giving out a loud, threatening screech as it widened its 'mouth'.

With the exception of mass union ships, Tanikaze Nodoka knows of the existence of giant Gauna biomasses. But never have she seen an individual Gauna that's nearly fifty times the size of Yukimori before. Just barely winning control over her primordial instincts to run away was hard enough. But having to confront the giant Gauna while securing her objective was a different story. Slowly tightening her grip on one of her control levers, Nodoka was quick to realize the immediate threat confronting her. Easily inside the striking distance of the Gauna standing above her, she cannot afford to make any mistakes.

"...Nodoka, please! Forget about me! Run away!"

Lying on the ground beside the Yukimori was the ravaged remains of Sidonian Type 19. Luckily for Nodoka, the cockpit seems to be intact as its pilot desperately cry out through the emergency communication channel, urging Nodoka to flee. At the same time, a second voice echoes through a second channel linked to Yukimori.

"...Nodoka! It's Ko! Where are you?! Answer me!"

Deciding to stay silent, she had tried to calm herself down with a couple of deep breaths. While she felt terrible ignoring the two voices, she can't bother to answer any of them at this moment. Shifting her vision towards a nearby display screen, Nodoka could see she only have 3 CPP remaining. Even her Heigus count was low. All she could rely on now are her Kabi-blades. Though Yukimori's cockpit was temperature-regulated, Nodoka couldn't help but to sweat from her difficult situation. Within the confines of Yukimori, she could smell the faint of sweat that was accumulating. Mixed with the already foul odor of oil and cleaning alcohol lingering about, it was starting to affect Nodoka concentrate...


	2. Chapter 1 - Old Arrivals

**Chapter 1**

 _— Few months earlier —_

 **Somewhere in Space - Lem IX Outer Ring**

Travelling through along edge of the massive planetary ring of Lem IX, two lonely Gardes swiftly makes their way through a field of astroids inside their field of vision. Locating the largest one within their area, both machines prepare to descend onto its surface.

"This Garde is so stiff…I hate it…I want to ride on the Yukimori back on home."

"Oh, don't be such a baby Nodoka. The Type-23's aren't that bad."

While it's not well made for offensive combat, the newer Type-23's highly modular design allows them to perform general tasks much better than previous models. Even the immense pull of massive gas giant, the Type-23's enhanced mobility modules makes light of the planet's gravity, even without boosters.

Courtesy of Toha Heavy Industries, each machine had expensive mining equipment strapped onto them. Despite Lem-VII being a resource-rich world, it lacks a certain exotic material that could only be found in abundance on Lem-IX's planetary rings, hence the current mission. However, since the demand for this material is quite low, only the small number of Gardes were needed for the job.

Nodoka, who was in the leading machine, was the first to land as it gently descend onto the astroid surface. The Garde's propulsion generated tiny dust clouds below the Garde's torso. To her right, the vastness of Lem-IX's teal-ish surface blocked the entirety of the universe beyond her Grade's external camera.

It was said that the mixture of clouds and floating islands on Lem-IX gives the planet a real fantasy-like touch. But in reality, unless you have entered the planet itself, it was difficult to see past the thick layer of gas suspended on Lem-IX's upper atmosphere.

In direct communication link with the other Garde, Nodoka could see the other pilot via a live feed on their peripheral monitors. On the upper right corner of her forward display, she could see the inside of a Garde her own as well at the pilot, a pink-haired companion, behind the controls. Though each Garde is contain highly sophisticated guidance system, she could see Honoka Ko (炬) moving her head as if to make sure that her maneuvres were executed correctly.

Whether it was she got used to piloting Gardes without helmets back on Lem-VII's surface or whether she just like piloting their machines without helmets, Nodoka could see Ko's unhindered ponytail swaying in the background. In fact, Nodoka herself is currently piloting helmet-less. Seeing her partner moving her machine as it is, Nodoka spoke through the feed.

"Ko."

"What is it Nodoka?"

As the Garde slowly makes its way onto the surface, Nodoka nonchalantly responded.

"Speed things up, would you?"

Annoyed by Nodoka's senseless statement, the pinked-hair pilot rebuked her remark.

"Shush. We're way ahead of schedule anyways."

Circling around Nodoka's machine, Ko too has landed onto the astroid's rocky surface. But whereas Nodoka's landing proceeded with nothing in particular happening, small beeps began to ring inside Ko's cockpit, warning of system errors.

Unlike Nodoka's landing, because the landing Ko performed seem so poorly executed from an outsider's perspective one could say that Ko botched her landing. But that is where they'll be mistaken. Given the unique circumstances she was placed in, Ko did a particularly stunning job landing her craft.

In mere fractions of a second, Nodoka's own machine began to beep. After pressing several buttons by her control lever, Nodoka manually stopped the never-ending racket that was beginning to irritate her. Stopping the same noise on her end, Ko pulled up a list of her Grade's functionality just to see where the problem was located. Of the many functions that was still running in perfect condition, a few lines in the list were highlighted in red.

Closing that screen from the monitor, Nodoka began to lift her arms above her shoulders. Having been trapped inside her cockpit for nearly two hours, Nodoka took this chance to stretch her tired body.

"Error 520. Seems like this month's report was accurate after all."

After ridding the same issue that was plaguing her own machine, Ko yawned.

"Yeah, but I didn't expect it to be that strong though. Haven't done a high speed S-maneuver in ages."

"Long-range communication with Lem-VII just went down and I'm not receiving anything from the Mizuho (水保) as well. I guess we're by ourselves for now. "

Based on the report that Nodoka had mentioned, a coronal mass ejection from Lem would remain in their area for at least another half an hour before the whole mass pass through the sector. Coursing around the Garde's resilient frames, the invisible solar storm engulfs Lem-IX's outer rings as it heads directly towards the planet below. There was now a bit of white noise appearing through the video feed, but that was a relatively minor issue at the moment as both pilots began to stare planet side.

While their situation does seems to have turned for the worse amidst an on-going solar storm, it doesn't feel terrible at all for the two pilots. In fact, it was quite the refreshing experience. Crossing her arms, Ko lean forward on her cockpit.

On top of being ahead of schedule, there's no one supervising them at the moment due their unusual circumstances. There's nothing wrong sneaking in a little bit of free time into their schedule. Especially if they're able to marvel at one of the universe's most astonishing event the human eyes could see, the aurora borealis.

With Lem-IX's unique atmosphere, an aurora on Lem-IX was nothing like that of those back on their home settlement. Painting as far as their eyes could see, there's something unique about the enormous aurora that would just leave anyone in awe. Neither pilots could pinpoint exactly what that is.

Shielded both by the planet's immense size and the flowing solar storm, little did they know about the shadowy figure that's approaching from outside the system…

 **Lem Orbital Station - Lem-VII Low Orbit**

"…I don't believe it…vice commander!"

Looking behind him from his post, a young technician turns around to inform his superior of his unexpected discovery. Riddled with bed hair, puffy eyes, it would seem like a man that hasn't slept for days. Looking around, however, anyone could tell he was not the only one in terrible shape. More appropriately, almost everyone in the station, male and female, were displaying the same 'exhaustion' that man was displaying. Nevertheless, this man seems rejuvenated from what he found, though not in the the good way it would appear. Breathing heavily, the technician tries to find the words that was lost in his mouth.

Standing by a control panel, a white-haired commander who looks no older than himself peered in his direction. Curious on what was going on, she pushes her body away from her position towards the technician's post. Undergoing routine maintenance, the artificial gravity generator was temporarily shut down, movement inside the command room where similar to that empty space. Floating towards the technician, she grabbed a nearby rail close to him to stops herself from moving any further.

"Slow down. There's no meaning in reporting anything if it's not comprehensible, right?"

She knows everyone in the station was on edge after losing contact with Sidonia. At the speed that Sidonia was travelling in the past decade, there was no way that the seed ship would just vanish from their detection like that. There are many members in that room who worked tirelessly to find the problem. Even the station commander himself had travelled to the surface below to speak with the council on the subject matter. In his absence, Seii Yuuko (ユウコ) must remain collected, if she want the the station run properly its current state.

Seeing his commander beside him, Yuuko could noticed the man loosening up.

"So…what is the problem?"

Taking a deep breath, the technician sat back down, pulling up a few screens so that he can explain to her. Though young, he seems to know what he's doing. There was no question as to why he was assigned to such an important position, despite his age.

"I can't believe it myself, vice commander, but this…"

Enlarging a certain area of Lem's system map, he projected what he found onto the station's main screen, currently blank. Others who was also began to look at the main screen began to to grow restless. The chatter in the room began to grow in volume. Filled with confusion, the commander stares blankly at the projection.

"That can't be right…have you verified the source?"

Nodding his head, he confidently pressed his case.

"I've checked our sensory arrays over and over again this past hour. I even check with our probe on Lem-X. It's still there."

"There must be a mistake…the Mizuki should be with Sidonia heading towards SC271…"

Flashing on the display, a blue triangle could be seen coming from beyond the Lem system. Under the blue triangle was the name many people has not seen for many years.

Mizuki, the original Tadugane-class warship that was assigned to Sidonia as its escort. If they were to check the ship's electronic signature, there was no denying that fact that the ship has returned to the system. Based on its trajectory, the ship is currently en route to this orbital station. However, at the speed of which it's travelling with, the time projection showed that it's arriving in a few days, a speed far too unusual for a ship of that caliber. Still quite skeptical, a shaken Yuuko demanded the technician to given her a visual confirmation.

"How did no one manage spotted her before this? Visual arrays. I want to see it now."

Bringing up what the interplanetary sensors are picking up, the expression of panic spread throughout the room. Battered and filled with holes, it really was the Mizuki, though the ship itself barely manages to move through space using its secondary thrusters.

"Aside from her signature, I can't seem to pick up any of Mizuki's signals…"

While she have never personally seen the legacy ship in combat, Yuuko has seen the ship itself in battle from old combat logs dating twenty years prior. There were many questions coursing through her head at the moment. What could possibly happened to it? Where was its fleet? Where was Sidonia? The vice commander's grip on the rail felt weak as her arms began to tremble. Bringing herself closer to the rail, she managed to shake off her trembling.

"Are you sure it's just the Mizuki? You don't see anything else?"

"It's just the Mizuki, ma'am. I don't see anything else."

After taking a few seconds to absorb what she had just learned, Yuuko pushed herself back to her original position. For the past few months, nothing seems to be going well for the vice commander at all. Lightly patting her face before getting herself pumped up for the work ahead, Yuuko rose her dominant arm forward.

"Raise the station's alertness level to yellow. I want contact with the surface immediately…"


End file.
